1. Field of the Invention
This invention relates to an intermediate bearing for the propellar shaft of a motor vehicle.
2. Disclosure Information
Intermediate bearings have been used with the propeller shafts of motor vehicles for many years. One example of such a bearing is shown in German Auslegeschrift (Published Specification) No. 20 61 625, in which there is interposed between two rigid casing parts a resilient deformation member of rubber or an equivalent material which is connected to said casing on its outer periphery by means of webs which contact one or both casing parts and which comprises on its inner periphery a receiving means for a bearing for a propeller shaft. This construction also includes stop or damper members which are integral with the resilient material of the deformation member and any necessary alteration of their elasticity is done by using inlays.
This known intermediate bearing has a disadvantage in that the resilient deformation member is joined by vulcanization to the rigid casing parts, which is relatively complicated and expensive. In addition, this known intermediate bearing has the disadvantage that the recesses between the web members and the stop and damper members are open, as a result of which dirt can settle in these recesses during the normal operation of the motor vehicle. Further, there are no provisions for damping pivoting movements of the propeller shaft.
Another construction for an intermediate bearing is shown in German Gebrauchsmuster (Utility Model) No. 81 12 477, which on its inner periphery comprises a receiving means for a bearing for a propeller shaft, with the receiving means being constructed in the form of a universal ball joint in order to permit angular deviations of the driveshaft. This known intermediate bearing too has the disadvantage that the resilient deformation members are joined by vulcanization to the rigid casing parts, which will not permit the intermediate bearing to damp angular movements of the propeller shaft.
Those skilled in the art have designed a plethora of elastomeric mountings for positioning a center bearing within its mounting bracket. Examples of such designs are shown in the following U.S. Pat. Nos.: 2,893,790; 2,906,572; 2,927,825; 2,963,106; 3,306,679; 3,309,154; 3,325,230; 3,704,922; 3,743,365; and 3,961,829. Each of these designs, as well as those disclosed in the two additional references cited above, suffers from a common functional inadequacy. This inadequacy stems directly from the fact that each of these designs is intended to function by loading the elastomeric elements in compression rather than in a tension mode. This is significant because elastomeric elements do not function as well to absorb vibration when they are subjected to compressive loading as opposed to tensile loading. The present invention, however, overcomes the difficulty of compressive loading by prestressing the web elements of its resilient deformation member in tension in order that compressive loading will not normally occur during operation of the device. Moreover, this tensile positioning of the webs of the resilient deformation member of the present invention allows the resilient deformation member to be economically positioned by means of apertures formed in the outer casing of the intermediate bearing.